Anchor tags href attribute is automatically prepended with domain name

I have a site hosted on netlify using a custom domain name, built with gatsby that uses continous integration via github.
Everything is working great with my site except one thing that only occurs only on the live site.
To to be clear, this issue does not occur locally, I only see it when deployed on the netlify host.

The issue I am seeing is that anything in the href attribute of an anchor tag is prepended with the domain name of the site so result is that all external links using an anchor tag result in a 404 error.

For example if my site is hosted via netlify with the domain and I have an anchor tag on my index page linking to an external site like this: Check out this site
When the link is clicked the browser tries to go to
Of course what I want is the browser to take me to just: https//

Is there some type of default redirect/rewrite happening? I have not configured any but my deploy log does contain this:
3:25:40 PM: success write out redirect data - 0.001s

Thanks for taking a look at my issue.

I found my own problem and it was very silly.
I had a syntax error in my URL notation, I was missing the double forward slashes after the semi colon so Gatsby thought it was a relative path and was prepending it on-the-fly.
So changing <a href=""> Check out this site </a>
To <a href=""> Check out this site </a>
fixed it.
Definitely not a netlify issue. Operator trouble :wink:

awesome. thanks for sharing what you figured out!